Submarine telegraphy.



No. 733,556. PATENTED JULY 14, 1903.

A. MUIRHEAD.

SUBMARINE TELEGRAPHY.

APPLICATION FILED nm 27. 189 8.

H0 MODEL.

UNITED STATES Patented July 14, 1903.

A PATENT OFFICE.

SUBMARINE TELEG RAPHY;

SPECIFICATION forming part of Letters Patent N 0. 733,556, dated July 14, 1903. Application filed December 27,1898. eel-a1 No. 700,394. (Non'iodL) To all whom it may concern/.-

Be it known that LALEXANDER MUIRHEAD, a subject of the Queen of Great Britain, residing at Shortlands, in the county of Kent, England, have invented certain new and useful Improvements in Submarine Telegraphy, of which the following is a specification.

My invention relates to submarine telegraphy; and it consists principally in providing such cable-circuits with improved means and certain combinations and organizations of parts for transmitting and receiving signals, and whereby an increase of speed in working the said circuits is obtained and other conveniences and advantages secured.

In the accompanying drawings, which are diagrams, Figure 1 depicts a typical way of carrying out my invention, and Fig. 2 serves to show certain modifications attendant upon the transposition of the transmitting and receiving circuits.

Both diagrams show connections for duplex working,C representing the cable and O the artificial cable, though obviously my invention is applicable to other cable-circuits.

T represents the transmitting instrument, which may advantageously be an automatic transmitter, such as that patented to me by prior Letters Patent of the United States, No. 577,534, and it is so indicated in the diagrams; but other forms of signaling-keys or their equivalents may be employed.

As will be understood, B indicates the batteries; E, the earth connections, and S S S indicate condensers.

According to myinvention I employ in the sending} circuit a selfinductance coil L, joined up in parallel with the key or transmitter T and its battery B. The said instrument L is constructed Without iron or other magnetic material, and it consists of a series of coils whose inductance is of suitable amount relatively to the capacity of the sending-condensers S S The contact-levers of the automatic transmitter .(or the signalingkey) are so connected up to the sending-condensers as not to short-circuit the self-inductance coil after battery contacts; otherwise the extra current which arises in the self-inductance coil immediately after breaking contact with the line-battery will not flow into the sending-condensers to assist in neuline-battery the cable is put to earth directly after the application of the line-battery. In the present case the cable instead of being put to earth direct is required to be connected through the self-inductance shunt to earth, so that the extra current created in the coils of the shunt may be utilized to accelerate the discharge or neutralization of the charge in the sending-condensers. The object of so combining with the sending-condensers S S and the key or transmitter T a self-inductance coil in the sending-circuit of the system is to provide a ready and sufiicient means of regulating, by reason of the extra current in the self-inductance coil, the amount of curb required to produce the most rapid changes at the beginning of the cable, and thus to obtain the best results in speed and sharpness or clearness of signals.

In the receiving-circuit of the system I employ by preference the usual siphon recording instrument, as indicated at R; but it may be any other suitable instrument-ality, and

there may be a receiving-condenser S According to my invention Iemploy in the receiving-circuit, as an adjustable shunt, an instrumentality L, consisting of a series of self-inductance coils Without iron'or other magnetic material in their construction, whose inductance can be varied readily in relation to the resistance of the receiving instrurnent and the capacity of the receivingcondenser employed. When the receiving instrument and receiving-condenser S are thus shunted by the self-inductance coil L, more sudden changes are attained in the circuit of the recorder. ing out of the cable encounters only a simple resistance in the loop-that is, both the selfinduction of the shunt and the capacity of the condenser are canceled in their effect. All the first impulses of the current flow The main current flowthrough the recorder, the steady current through the self-inductance coil L. The more rapid the variations of potential at the sending end the more of the resulting disturbance at the receiving end takes place in the recorder-circuit. In other words, the effect of the self-induction in the shunt is to divert all the rapid changes of the received current into the circuit containing the re corder or receiving instrument and to permit only the slow flow of the main current through the coils of the shunt.

For the purpose of this invention I prefer to construct the last-mentioned shunt of a series of flat coils whose mean diameter is about three and a quarter times their sectional width,the section being round orsquare, without iron.

As will be seen by comparison with the two diagrams, the receiving instrument R, together with the receivingcondenser S shunted in the manner described, may be placed either between the cable '0 and the artificial cable 0, as in my so-called double-block system of duplex and as shown in Fig. 1, or between the index of the low-resistance rheostat R (that is usually located at the apex of the bridge) and earth, as shown in Fig. 2. In the latter case I divide the lastmentioned self-inductance coil into two parts, such as those indicated at L L adjustable in connection with the usual blocks of condensers, and shunting the latter for the purpose of duplex balancing, both in resistance and in inductance.

In Fig. 2 the inductance-coil Lis,asin Fig. 1, in a shunt around the transmitter T.

In order to facilitate the final duplex balancing of the artificial cable 0 against the cable O, I construct the coils Ct of the rheostat R in the same manner as the hereinbefore-mentioned self-inductance coils, so as to have self-inductance of an amount which can be readily varied in order to counteract the effect on the duplex balance of that of the real cable. To the same end I may extend the principle of the self-inductance coils of the rheostat R and insert adjustable self-inductance coils of low resistance between the sending-condensers S S and the cable and artificial cable, respectively, as indicated at L L These coils facilitate the duplex balancing by diminishing the rate of variation of potential due to the outgoing current from .the signaling-batteries at the points where the cable and artificial cable are joined to the receiving-circuit, thus producing less jar on the receiving instrument.

What I claim, and desire to secure by Letters Patent of the United States, is-

1. In a duplex submarine-telegraph circuit, the combination of a transmitter and its battery, sending and receiving condensers, a rheostat, a receiver, self -inductances serving to regulate the amount of curb required to produce the most rapid changes at the beginning of the cable, further self-inductance serving as a shunt to the said receiver and its condenser through which the steady current passes while current impulses or rapid variations of potential operate such receiver, and other self-inductances serving to facilitate the final duplex balancin 2. The combination with the line or cable, artificial line, transmitter and sending-con densers interposed respectively between the cable and transmitter and between the artificial line and transmitter, of a self-induct ance coil connected in parallel with the transmitter and battery and through which the line is put to earth when disconnected from the battery, the self-inductance coil thereby serving to regulate the amount of curb required to produce rapid changes at the beginning of the cable, substantially as set forth.

3. The combination with the line or cable, artificial line, transmitter and sending-condensers connected respectively between the transmitter and cable and between the trans mitter and artificial line, of a receiver and condenser connected between the cable and the artificial line and a self-inductance coil in shunt to the receiver and condenser and through which the steady current passes while currentimpulses of rapid Variations of potential operate the receiver, substantially as set forth.

4. A duplex submarine-telegraph circuit having, in combination, a transmitter and its battery, sending-condensers, a self-inductance coil joined up in parallel with the transmitter and its battery, a rheostat, a receiver and its condenser, and a self-inductance coil serving as a shunt to such receiver and condenser.

In testimony whereof I have hereunto subscribed my name.

ALEXANDER MUIRHEAD.

Witnesses:

A. F. SPOONER, J. SUTTON. 

